Materialize CSS materialize css Rails form_with input validation

materialize_form.rb

# config/initializers/materialize_form.rb
#
# So that you have Materialize CSS validation message  https://materializecss.com/text-inputs.html such as
#
#     <div class="input-field">
#       <label for="company_title" class="active">Title</label>
#       <input type="text" value="" name="company[title]" id="company_title" class="invalid">      
#       <span data-error="can't be blank" class="helper-text"></span>
#     </div>



ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  if html_tag =~ /<(input|textarea|select)/
    error_class = 'invalid'

    doc = Nokogiri::XML(html_tag)
    doc.children.each do |field|
      if field['type'] != 'hidden' || field['type'] != 'file'
        unless field['class'] =~ /\binvalid\b/
          field['class'] = [field['class'], 'invalid'].join(' ').strip
        end
      end
    end

    if instance.error_message.kind_of?(Array)
      err = instance.error_message.uniq.join(', ')
    else
      err = instance.error_message
    end

    node_set = Nokogiri::XML::NodeSet.new(doc)

    span = Nokogiri::XML::Node.new "span", doc
    span['data-error'] = err
    span['class'] = "helper-text"
    #span.content = "in case you have any concent"

    node_set << doc
    node_set << span

    node_set.to_html.html_safe
  else
    html_tag
  end
end

new.html.slim

# app/views/company/new.html.slim

= form_with model: @new_company do |f|
  .input-field
    = f.label :title, 'Title'
    = f.text_field :title